Question

2. An animal scientist crossed a strain of large guinea pigs and a strain of small guinea pigs, and finds the Fı are phenotypically uniform, with an average size intermediate between the two parents. She allows the Fı individuals to inter-mate, resulting in 1014 F2 individuals (guinea pigs are prolific). In the resulting F2 generation, 4 guinea pigs were in the smallest size class (which is the same as the small parental line). a. From these data, estimate the number of segregating genes in the Fı affecting size in this cross (show your work). b. Label the genes alphabetically (A, B, C, etc.) and assign genotypes to the: Large parental line: Small parental line: F1 population: c. Estimate the number of the expected F2 classes (different F2 phenotypes for size) (show your work).

Answer 1

2 4 Guinea pigs are smallest size out of 1014 & gensation. ( ) = 153.5 tors) so tory progeny in generation is 256. - 256 indivisual can only formed in to generalis after selfing, so 8 gemete will be u heterogggous in nahere, so (2) 4 = 16 different type of gamete formed and after selsing it will form 16x16=256 Indivisual, so gamete will be 4 heterozygous in nature, 6) gene assigned ABCD lasge parental line. AABB CC DD small parental line, dabbee ad s population: Aabbladd ( Expected to Classes are 256